The Science of It
by mojober
Summary: "How could anyone so smart not understand such a basic human need as love?" Molly spends the night with Sherlock.
1. Chapter 1

Molly Hooper was half asleep when she heard a knock at her door.

She lifted her head and peered at the clock. It was almost midnight. Who the hell could it be at this hour? It was probably her drunk neighbor again thinking this was his flat. Maybe if she ignored him, he would go away. She lowered her head and sunk back into the blankets and waited. It was quiet. Good.

He knocked again and Molly groaned.

She threw back the covers and snatched her robe off the floor.

"This isn't your flat Robert!" she called out, her stocking feet padding across the floor. "You have to go up one more flight!"

More knocking, this time more insistent.

Molly unlocked her door but left the chain on as she opened it.

"Robert, it's really late ..."

It wasn't Robert.

It was ...

"I need somewhere to stay," Sherlock said, staring back at her through the narrow opening. He was covered in snow and his breath was white. He tapped a gloved finger on the chain separating them. "These are completely useless."

Molly's mouth fell open in shock. It was bad enough he showed up at her work unannounced but now her flat? She glanced down at her flannels and terry robe and remembered she hadn't even bothered to take a bath before climbing into bed. It had been a long day, which was about to get even longer.

"You look lovely," he said, giving her _that_ smile. That smile that meant he wanted something and right now, he wanted into her flat.

Molly stared back at him, her sleepy brain still trying to fathom why Sherlock Holmes was wanting to spend the night here. She decided it had to involve work. It was all he cared about, wasn't it? Work. Work. Work. It couldn't _possibly_ be for anything else, could it?

"Are you in some kind of trouble?" Molly asked, her brow furrowing. She didn't feel like having her building blown up or being kidnapped or any of the other horrid things that his flatmate had to endure.

"No," he said, his smile fading fast. Now, he just looked at her with _those_ eyes. "It's very cold out here so could you just let me in?"

"Okay," she said, finally giving in. She shut the door, unfastened the chain and let him inside.

"Thank you," he said, stepping into her dark flat. He looked around and Molly cringed at what he would deduce from her humble abode. Toby appeared out of nowhere and proceeded to rub himself against Sherlock's leg. He made a dour face as he looked down at the offending creature. "I hate cats."

"His name is Toby," Molly said, scooping him up her arms protectively. Sherlock proceeded to wander into her kitchen, his eyes darting everywhere. Molly remembered her manners despite the fact Sherlock didn't seem to have any. "Would you like a cup of tea?"

"Yes and some biscuits," he said, grinning at her if she were some sort of waitress. Molly made herself smile back and put Toby down.

"Okay," she said, heading toward the stove.

It was definitely going to be a long night.


	2. Chapter 2

In the dim light of her kitchen, Molly sat across the small table from Sherlock. He was quietly tapping into his cell phone and ignoring her as usual. He did, however, eat three biscuits along with his tea.

Normally, she was an absolute mouse in his presence. All he had to do was use his charms and she was powerless against them. He'd gotten her to do all sorts of things at Bart's but they weren't at Bart's now. They were in her flat in the middle of the night. Somehow, that equaled things out for Molly. She kept staring at him until finally he spoke.

"You can go back to bed," he said, not bothering to look up. His tone was dismissive, as if she were child being sent away. She wasn't going anywhere.

"I can't sleep if you're in here," she said, then decided to just ask. "What are you doing?"

"Working a case," he replied, his fingers still typing away.

"No, you're not," Molly said firmly.

That made him stop and look up.

"You ate three biscuits," she pointed out. "You don't eat when you're working. You said so yourself."

Sherlock looked impressed, but annoyed.

"Bravo, Molly," he said, finally setting his phone down. He folded his hands together and brought them to his lips in thought. "What else?"

"If this isn't about work, then it's personal," she said, watching for a reaction. "Since you aren't actually personal with anyone except John, I have to assume he's thrown you out for some reason."

"I'm personal," he said, taking offense to that word. "I'm personal with you."

To that, Molly let out a laugh.

Her experience with Jim had made her take a serious look at her relationship, or lack thereof, with Sherlock. He used her, plain and simple, just like Jim. She knew she was stupid for letting him but she had thought perhaps deep down he cared for her.

She was wrong.

He didn't even bother to check on her after the entire Jim incident was over or ask how she was. He merely showed back up at Bart's two weeks later as if nothing had happened.

"No, you flatter me to get what you want," she said, the late hour and lack of sleep making her blunt. He looked even more offended now. "You certainly don't mean any of it."

"I most certainly do. I'm merely stating facts," he said, sitting back in his chair. "Like right now, your lips are the perfect shade of pink for your complexion."

"I thought my mouth was too small," Molly countered. "And I'm not wearing any lipstick."

"You've also developed wrinkles on either side of your mouth," he said, motioning around his own. "It's a bit premature for 31, don't you think?"

Molly knew exactly what he was doing. He was trying to distract her from the matter at hand. She took a deep breath and tried to ignore that last comment.

"So John threw you out," she said pointedly.

"John did not throw me out," he replied, making her sound stupid for saying so. He shrugged dismissively. "I left."

"Why?" Molly pressed, raising her eyebrows expectantly.

"How is that relevent?" he asked and Molly wanted to scream. What was wrong with him?

"Because you're in _my flat_," she said, emphazing the last two words for him. "At one o'clock in the morning, I might add."

"All that matters is my work," he said, sliding his chair back and standing up. Sherlock paced about and scratched his fingers through his hair. "I make that perfectly clear to everyone. I can't be bothered with the mundane, the trivial or the emotional attachments of those around me."

That last bit made Molly stop and think.

It took her a few minutes but she finally figured it out.

He really was unbelievable.


	3. Chapter 3

"This is about John," Molly said, giving him a knowing look. "John and Sarah."

Molly met Sarah through her blog the night went Jim was missing, along with John. It didn't take them long to figure out the disappearances were connected and through whom. They went to the police together and waited. In those dark hours, Sarah made more that few comments about Sherlock not liking her much. Molly assured her he didn't like anyone.

"I don't need them distracting me when I'm trying to work," he said, moving about anxiously.

"You're not working right now," she reminded him, standing up. "Is that the problem?"

Molly knew all too well this was what Sherlock was like when he was bored. Even she could barely stand to be around him during one of his fits. He practically tore the mortuary apart one night looking for something, anything to keep his mind occupied for a few hours. She feared for her flat and for Toby.

"No," he said, stopping for a moment. His eyes darted all around in thought as if he was trying to decipher some complex puzzle. "I don't know why he bothers. I swear he just does it to irritate me."

"Does what?" Molly asked, glaring at him now. "Have a relationship with someone who cares about him? Oh yes, I can see what a terrible inconvenience that must be."

She wasn't really talking about Sarah as much as she was talking about herself. It had taken her weeks just to get up the nerve to ask him out for coffee and he didn't get it. That's why when Jim asked her out, she jumped at the chance. She could only imagine what Sherlock really thought of her for that.

"I don't care what he does," he said, scratching his fingers through his hair again. "He just needs to do _it _somewhere else."

Suddenly, Molly realized what _it_ was.

"Are you serious?" she said, folding her arms defiantly. Her own frustrations with Sherlock were getting the better of her. She'd had enough of his lack of human emotions. "Just because you never have _it _isn't a reason to keep John and Sarah apart."

It was the wrong thing to say.

"I have _it_," he said adamantly, coming toward her straight on. He looked highly insulted she would even suggest such a thing. "I'm extremely good at _it,_ actually."

"Really?" she said, her doubtful voice much more steady than she was with an irritated Sherlock backing her into the counter. There was tension in the air that had nothing to do with John or Sarah. This was about them. _Finally. _

"Yes, really. Shall I prove it to you?" he said, staring her down. Molly looked up into those eyes and he was serious. Her heart pounded hard in her chest as it answered for her.

"Yes."


	4. Chapter 4

_Author's Note: Thank you all so much for the feedback. It really keeps me going. I wasn't sure how a Sherlock/Molly story like this was going go over. Glad you are enjoying it! _

* * *

With that one word, Molly was lifted onto the counter.

They were face to face now, his body between her knees as he leaned in to kiss her. It wasn't a gentle kiss either. It was intense and Molly was glad she wasn't standing. She clutched onto his arms just to steady herself against the sheer excitement of it all. Here, the man she'd been in love with for months was kissing her with intent to do more. Much more.

It took her a few seconds to return the kiss, her mouth yielding easily to his. His tongue swept against hers as his hands found their way to the belt on her robe. She let out a little whimper as he pulled the knot free.

This sort of thing never happened to Molly, but she found herself adapting quickly. Her hands slid up into his hair, messing it up even more than what it already was. His mouth slid off hers for a moment and he pulled back, his eyes flickering over her face as his fingers touched the vein on her neck.

"Your pulse is at 120 already," Sherlock said, smiling to himself. His hand moved lower to cover her left breast, his thumb sliding slowly over the peak. "Definitely aroused."

"You think?" Molly said teasingly. She bit her lower lip as she pressed a hand to his cheek. Molly wondered if he felt any of this the way she did. He merely blinked back at her.

"You _do_ have protection," he said, his tone questioning. Obviously he didn't think she regularily engaged in such matters.

"I _do_," she informed him, hoping the dusty box was still in the cabinet in her loo. Thankfully, things hadn't gotten this far with Jim.

"Good," he said, his eyes locked onto hers. Molly had the feeling he was expecting her to back out at any second but she wasn't going to. When else would this ever happen? At Bart's on some metal trolley in the middle of a case? In the lab while he was waiting for results?

"I'll get them now," she said, feeling more empowered than she ever had in his company. Molly Hooper was not a mouse and she was finally going to prove it. She slid off the counter and reached for his hand. "My bedroom is this way."

"I know," he stated, his fingers catching around hers as she led him to it.

"I'll just be a minute," she said, letting him go so she could disappear into the loo. She shut the door, pressed her back against it and exhaled every ounce of oxygen out of her lungs.

She was really going to do this, with him, in her bed. She couldn't help but feel a wave of panic, then excitement, then panic again as she knelt down and opened the cabinet.

"Please be in there, please be in there," she muttered under her breath. There were boxes of various feminine things, toiletries and towels. She was trying not to make too much noise but she was becoming frantic the more she searched.

Finally, she found _the_ box.

It wasn't empty or expired.

Molly put two of them in the pocket of her robe, shut the cabinet and stood back up. She composed herself the best she could, then opened the door. Her eyes filtered through the darkness to find Sherlock sitting on the edge of her bed silently undressing.

"What are you doing?" she asked softly, walking over. She set the packages on her nightstand before stopping in front of him. His jacket and shoes were off and he was unbuttoning his shirt. Molly put her hand over his to make them stop. "I would like to do that."

"Why?" he asked, his brow furrowing. He seemed flustered by her request. "Isn't this more efficient?"

"Not the point," she said, realizing he still didn't get it. How could anyone so smart not understand such a basic human need as love? Not that she was any great expert at it but Molly was starting to think she had the advantage. In fact, she knew she did.

Molly sat down, leaned in and kissed him. This time, it was slow and full of every repressed emotion she'd been feeling for months. She wrapped her arms around his neck and drew him back onto her bed.


	5. Chapter 5

They landed in the middle of her bed and onto their sides. She ended the kiss, then stared up into his eyes for a moment trying to read him. He seemed distant, but focused on the task at hand. Her fingers went up to his shirt and she finished unbuttoning it for him. She ran her hand over his chest and pressed her lips together to keep from gasping.

He was fit, really fit.

Molly pushed the shirt eagerly off his shoulders, wanting to see more. Sherlock shifted just enough to pull it away completely. Before she could start in on his trousers, his hands were tugging at her robe. Molly wriggled out of it and he immediately tossed it out of the way.

"These are the _worst _flannels ever," he said, giving her a look of disapproval as he quickly unbuttoned them.

"Next time, I'll wear something better," she assured him, watching his hands as they worked their way down. She lifted up so he could remove her top. Her bottoms were next, off in seconds along with her knickers. His gaze traveled down, then back up her naked body as he studied her for a moment. Molly felt herself flush over. "What?"

"Just trying to determine the best angle," he said thoughtfully.

"For you or for me?" Molly asked, then explained. "I mean, I know what works best for me."

"Really?" he asked, mimicking her doubtful tone from earlier.

"Yes, really," she said, her fingers slipping down to his trousers to unfasten them. It took a bit of shifting around again but soon they were gone. Molly inched back up the bed, wanting to get under the covers. It was cold and he was quite warm. "Come here."

He did and with a few more adjustments, Molly pulled the covers over them both.

"That's better," she said, tucking herself underneath Sherlock. There were no words to describe the feel of his body against hers. Before Molly could wrap herself completely around him, he disappeared under the covers.

She brushed her fingertips over her eyes, closing them against the sensation of his lips. Molly tensed at every kiss as he worked his way down, hitting every sensitive place along the way. Sherlock wasted no time settling in between her legs, his mouth finding just the right spot.

It was bliss, sheer and utter bliss and Molly thought she might float away. She'd had this done to her many times but never quite like this. He knew exactly what to do and where to do it. Molly held her breath as her body started to quiver with pleasure. She moaned softly, unable to keep quiet one second longer. Every thought, every fiber of her being was lost in the moment that seemed to go on forever.

When it was finally over, her hands reached down to tangle her fingers in his hair. She drew him back up over her. He was smiling like the damn Cheshire cat.

"How was that?" he asked, his voice so low it made her insides shudder again.

"It wasn't bad," she teased, lifting her head up to kiss him. He turned his face away.

"Wasn't bad?" Sherlock said, with mock indignation. His arms slid under her backside to flip her over so she was on top. Molly's long hair fell like a curtain around them both and she swept it back out of the way. "That lasted 32.6 seconds."

"I bet you can improve on that," she said, straddling his hips with hers. She could feel him underneath her and she smiled knowingly. "Seems I'm not the only one who is aroused."

"How very observant," he said, his hands reaching for hers. He used them to push her up into a sitting postion, then stared up at her curiously. "Were you always like this? How did I miss it?"

"You weren't paying attention," she said, her hair falling back over her shoulder as she rocked forward a little. Sherlock sighed heavily, his hands pressing hers back to do it again. She repeated the motion several times before her eyes darted over to the small packages on the nightstand. He let go of her long enough to take care of things.

"Now where were we?" he asked. Molly answered by lacing her fingers with his before moving back into place.

"Right about here," she said, lowering herself on top of him.

Molly closed her eyes, overwhelmed by everything she was feeling. She wanted to remember every detail of this moment in case it never happened again. There was a good possibility of that and she knew it. She could practically hear him telling her this was merely a diversion and that there was no place for her in his logical world of deduction.

"Molly?"

She opened her eyes and found him staring up at her again.

"Sorry," she said, pushing those thoughts away. She began moving slowly, her hips sinking down then back up again. His palms pressed up against hers, changing her position somewhat. Molly gave him a look when she realized what he was doing.

"You'll thank me in about three minutes," Sherlcok said confidently. "Two if you go faster, which I would appreciate greatly."

"Would you now?" Molly said, keeping her pace slow on purpose. "I told you, I know what works best for me."

"If you insist," he said, letting her shift back to where she was.

It didn't take long for her to feel that wonderful pressure building up again. Molly did move faster, but only when she needed to. Her eyes fluttered close as everything inside her tensed, then released once more. She thought about counting the seconds, but she just wanted to enjoy it. He waited until she was finished, then pulled her down into his arms. She opened her eyes at the sudden motion.

"My turn," he said, rolling her onto her back again so he was on top. She barely had time to catch her breath before he started pistoning his hips into hers. Molly wound her arms and legs around him to steady herself.

She watched him, watching her as he kept going. He didn't even blink as his breathing grew shallow and uneven the closer he got. Within seconds, he was there. It was only then his guarded expression changed, his face registering the physical release. He stopped moving, his eyes shut as he collapsed into her arms.

Molly held onto him for a moment before he shifted off her. Sherlock turned over onto his back, arm across his forehead as his breathing slowed back down to normal. Molly turned onto her side to face him. He looked pleased with himself, which didn't surprise her at all.

"Verdict please," he said, lowering his hand to rest on his stomach. He turned his head and stared at her, waiting for her answer. Molly paused, pretending to think about it but there was only one thing she could say.

"It was _extremely _good," she admitted with a smile.

"I agree," he said, smiling back at her.


	6. Chapter 6

Molly couldn't sleep and seriously doubted he was.

They were lying on their sides, facing each other in the middle of the bed but not touching. His eyes were closed, his body still as she watched him breathe. She reached across to gently brush his bangs off his forehead.

"Stop," Sherlock muttered but she didn't. His hand reached up to catch hers. Instead of letting it go, he tucked it under his so she couldn't do it again. "What time is it?"

Molly lifted her head to peer over his shoulder at the clock.

"Half past three," she said, hoping he wasn't going to leave just yet.

She settled back down and was quiet for a while. There were so many things she wanted to say, but she knew it was best to keep her mouth shut. She didn't want to ruin this or whatever it was they had. She couldn't help but wonder what he was going to say the next time he wanted her to do something. Flirting seemed utterly pointless now. Molly wasn't sure she liked that.

"This doesn't mean you can do whatever you like at Bart's," she said, thinking out loud. Sherlock opened his eyes and looked at her. "I mean, there are rules."

"If this were all it took, I would've had _it _off with Stamford months ago," he said and Molly laughed. He did as well. It was a sound she hadn't really heard before. "You're underestimating your value."

"You're just saying that to get me to do _it _again," she said, sliding over his way. She nudged him onto his back and shifted her upper half on top of him.

"I'm saying it because it's true," he said, his hand moving up to her shoulder. He traced the curve of it with his finger, his eyes following the motion as if he was calculating the degree. "And you obviously want to do _it _again or else you wouldn't be all over me right now."

"Yes I would," Molly said, leaning forward to kiss him. She felt her lower half immediately start to ache with need. She couldn't remember the last time she felt so uninhibited but he didn't seem to mind. In fact, he seemed to like it.

The kiss was cut short by Sherlock reaching down to hook one of her legs over his hip. His hand then ran up her backside, again outlining her curves. He pushed her back onto her side so they could touch each other.

She slid her hand down his chest and over his taut stomach before moving lower. Her eyes flickered up to his face and she smiled. He was trying not to show any reaction whatsoever but the rather desperate look in his eyes the faster her hand moved was betraying him.

His hand came up to her breast, palming it first before his thumb started circling. Molly tried not to let that distract her from her task but it felt so damn good. There was a part of her that wanted to draw this out but the other part just wanted to get on with it. That part was winning.

"Hold on," she said, letting him go so she should reach over to the nightstand. She opened the package and helped him secure it on. She breathed a sigh of relief as she pulled him on top of her and let him sink right in.

"Do you want to be on top?" he asked and she shook her head.

"Show me the best angle," she said, winding her legs around him. Molly couldn't imagine things getting any better but he was so confident about it she wanted to find out.

"With pleasure," he said, his arm slipping underneath her hips to pivot them up. She twisted her fingers through his hair and let him adjust her however he wanted. He started to move and Molly felt the ache inside her intensify, wanting more of this and of him.

"Faster," she heard herself say, then felt him speed everything up. She quickly found herself on the edge, her hands clasping his shoulders as everything splintered away. She shut her eyes, focusing only on the pleasure sweeping through her.

It wasn't long before he was there with her. She could feel it and feel him. Molly opened her eyes and found him staring at her as if he was trying to sort things out. She wondered if he felt an actual emotion this time. She certainly did.

Before either of them could say anything, a faint chirp cut through the silence. His eyes immediately sparked as he untangled himself from Molly.

He reached down to the bottom of the bed for his jacket. He pulled out his cell phone, the screen softly lighting his face as he looked at the number before answering.

"Sherlock Holmes," he said, his voice rough from lack of sleep and sex. He sat up and listened for a moment. "On my way."

Molly felt her heart plummet as he shut the phone, then slid out of bed. She buried herself in the warmth of the covers and closed her eyes. She listened to him moving about the room for a few minutes and silently cursed whoever it was that called. Reluctantly, Molly pulled herself up.

"Where are you going?" she finally asked, unable to keep the disappoinment out of her tone. He was almost dressed already and stopped long enough to turn in her direction.

"There's been a murder," he announced, sounding quite happy about it. He had that look on his face, the one he always got when he was on a case. Anything he had been feeling for her, if he truly had at all, was replaced by the excitement of knowing there was something new to solve.

"Okay," Molly said, trying hard not to be emotional. This is what he did and who he was and she knew it better than anyone. It could be days, even weeks before she saw him again. He snapped up his jacket and glared at her.

"Well, don't just sit there," he said harshly as he shrugged into it. "Get dressed. You're coming with me."


	7. Chapter 7

"What the hell is she doing here?" Sergeant Sally Donovan said, gesturing at Molly. It was still snowing, covering the crime scene in a pristine blanket of white.

"She's assisting me this morning," Sherlock answered, holding the police tape up so Molly could slip under it. He walked on ahead to enter the residence, breezing quickly past Donovan.

"Assisting ... is that what you call it, Freak?" she said with a snort. Donovan stopped Molly before she could go any further. "I hope for your sake, you're not."

"Dr. Watson was unavailable," Molly offered as an explanation. "Believe me, the very _last _thing I wanted to do was get out of bed and come here."

"He shouldn't have bothered you," Donovan said, making a face. "Our people are certainly more qualified than Dr. Watson or you for that matter."

"I know," Molly said, figuring it was best not to argue with her. She'd dealt with Donovan enough to know how she was. After a few decisive moments, Donovan finally gave in.

"Go on," she said, letting her pass. "Just be sure to follow procedure."

Molly walked up the stairs and through the hallway. The house was dark, except for the rooms where the police were gathered. She recognized Inspector Lestrade immediately. She suspected he was the one who made the call. He turned and gave her the once over.

"Is Bart's mortuary making house calls?" he asked, zipping up his blue coveralls before handing her one.

"She's with me," Sherlock called out from somewhere in the next room. Lestrade's expression eased up at that. Molly removed her coat and proceeded to slip it on over her clothes. She put the protectors over her shoes, then snapped on a pair of latex gloves.

"Watch your step," Lestrade warned, moving back to let her through to join Sherlock. He hadn't bothered to suit up. She carefully stepped forward to examine the body.

The victim was lying face down and was naked from the waist up. In the center of her back, a number had been carved into her skin. Sherlock was kneeling beside her, carefully tracing that number with his latex-covered finger.

"One two five," he said, loud enough for her to hear. "This was made before death, correct?"

"Yes," Molly confirmed, standing just behind him. She'd long since detatched herself from feeling anything except the need to restore a victim's humanity. Sherlock, on the other hand, took such pleasure in these sorts of crimes. She could practically feel the energy coming off him as she moved closer to examine the body.

Molly carefully swept the woman's blond hair aside to expose the back of her neck. There was bruising she recognized immediately. She wanted to turn the body over, but knew she couldn't disturb it.

"She appears to be have been asphyxiated," she said, her eyes moving off the woman and to Sherlock. He stood up, drawing himself to his full height before turning to Molly. "One two five means what?"

"Something interesting," he said, obviously excited about it. He removed the latex and handed them to Molly before pulling on his leather gloves.

"Where are you going?" she asked as he moved past her.

"To fetch John. Surely he's done with _it _now," he said, giving her a knowing smirk. Sherlock wove his slender form between Lestrade and the others before slipping out of sight.

She stood there for a moment, staring at the space where he just was until Lestrade came toward her.

"Sorry," he said, apologizing for Sherlock. "He's always like that."

"I know," Molly said, stepping back into the other room. She removed the suit, protectors and gloves. He watched as she put her coat back on, fastening it up quickly. "Could I possibly get a lift to Bart's?"

"Certainly," Lestrade said, motioning for her to leave. "You'll have to wait outside while we finish up."

Molly nodded, then headed back to the door where Donovan still was. She gave her another disapproving look but let her be. Molly's eyes scanned the street, but Sherlock was gone. She reminded herself John was his chosen partner and not to take any of this personally. He was Sherlock Holmes and she was just Molly Hooper. One night wasn't going to change things.

She wrapped her arms around herself, trying to keep warm as the snow continued to silently fall. She was so distracted by all the commotion she almost didn't hear the beep of her cell in her pocket. Molly took it out and saw she had an incoming text message, which she immediately clicked to open.

_Would like to again._  
_SH_

Molly smiled to herself before texting back.

_Me too._  
_MH_

At the very least, things were going to be different.

The End


End file.
